by Donna Freydkin, USA TODAY

by Donna Freydkin, USA TODAY

Background: The daughter of NBC Nightly News anchor Brian Williams earned an English degree from Yale before pursuing her childhood ambition of being an actress.

She plays: Art-world aspirant Marnie. "You don't know what she's passionate about. What this season is really about is that before you become passionate about something, you have to figure out who you are," says Williams.

Up next: Guest-starring on several episodes of Fox's comedy The Mindy Project.

Jemima Kirke, 27

Background: The daughter of rock drummer Simon Kirke (Bad Company and Free), Kirke is a Rhode Island School of Design-educated painter who lives in Brooklyn with her husband, Michael Mosberg, and their kids Rafaella, 2, and Memphis, six weeks.

She plays: Free-wheeling newlywed Jessa. "I want to see her do more wacky (stuff), but I would also like to see her have a little more direction, a goal, an interest. She doesn't have an interest," says Kirke.

Up next: Painting in her new basement studio.

Zosia Mamet, 24

Background: The daughter of playwright David Mamet always wanted to act and skipped college to do it, on Mad Men and in the 2010 film The Kids Are All Right.

She plays: Wide-eyed naïf Shoshanna. "She's always putting her foot in her mouth. I've never felt so endeared to a character before. I want to hug her and tell her it's going to be OK," says Mamet, whose first name is pronounced Za-Sha.

Up next: The off-Broadway play Really Really, which opens Jan. 31.

Lena Dunham, 26

Background: The Oberlin graduate first broke out with her 2010 debut, Tiny Furniture, and is the creator/producer/writer/star of Girls.

She plays: Aspiring writer Hannah, who works in a coffee shop after being cut off by her parents. "The big thing I have in common with Hannah is the feeling that I should be able to say whatever I want. I feel like that is something we share. She does it and she feels like it's her right," says Dunham.

Up next: Working on her book, Not That Kind of Girl, which is set to be published by Random House this year.